1. Field of the Invention
This invention relates to conveyor devices and more particularly to such devices arranged for separating a continuous flow of articles into separate batches containing a desired number of such articles.
2. Description of the Prior Art
In the past, the separation of articles, particularly flat objects or sheets, which are continuously fed, into separate batches of desired size was accomplished by a number of devices such as are shown in FIGS. 1 to 4 of the present application. The identification of the figures illustrating the prior art and being here described is given in a later section of this application under the heading Brief Description of the Drawings. In the prior art structure shown in FIG. 1 and in FIGS. 2(A), (B), (C) and (D), there is shown a transport conveyor 1 and a sorting lever 2. With this type of apparatus, as is best shown in FIGS. 2(A), (B), (C) and (D), the articles or sheets travelled at a constant speed in the direction of arrow 4. To separate the first batch ( . . . A.sub.98, A.sub.99, A.sub.100) from the next batch which followed (B.sub.1, B.sub.2, B.sub.3 . . . ), it was necessary to sort them by opening or closing the sorting lever 2.
With this structure, however, the timing of the movement of the sorting lever 2 was important. As shown in FIG. 2(B), through variation of the space 3, it was likely that some sheets of the first batch (for example A.sub.100) would become mixed with the sheets of the succeeding batch and an accurate separating was difficult. Also, since the sorting lever 2 would cause the sheets of the succeeding batch (B.sub.1, etc.) to stop, there was the probability that the front edge of that batch would be damaged or that the sheets would be piled up as illustrated in FIG. 2(C). The latter result would cause the final arrangement of the sheets to be in bad array.
Another type of prior art conveyor apparatus is shown in FIGS. 3(A) and 3(B) and in FIGS. 4(A), 4(B), 4(C) and 4(D). The conveyor device shown in these Figures includes a supply conveyor 5, a sorting conveyor which includes belts 6a, 6b, 6c, 6d and 6e, sorting levers 7a, 7b, 7c and 7d, one such sorting lever being interposed between each pair of belts, and a transport conveyor 8. The supply conveyor is run at high speed while the sorting conveyor, including belts 6a, 6b, 6c, 6d and 6e, is run at a speed of about 20 to 50 percent of supply conveyor 5.
The functioning of this prior art conveyor device is best seen in FIGS. 4(A), 4(B), 4(C), and 4(D). These Figures show that when batch A is being sorted or separated from batch B, as the last sheet (A.sub.100) of the former batch ( . . . A.sub.98, A.sub.99, A.sub.100) passes the levers 7a-7d, the levers 7a-7d rise with respect to batch B (B.sub.1, B.sub.2, B.sub.3 . . . ) and, as FIG. 4(B) shows, B.sub.1 is pushed up. Through the friction of the levers 7a-7d, misalignment and jamming shown in FIG. 4(C) can occur. The sorting conveyor including belts 6a-6e and transport conveyor 8 carry the sheets to the sites of processing, but the aforementioned batch B must be stopped, even though the belts are still moving, before it can be sent on to processing so that it can be properly realigned.
As is shown in FIGS. 3 and 4, conveyor devices used in the past which employed rising levers had to have precise timing to avoid mixing the last sheet of one batch (for example A.sub.100) with the first sheet of the following batch (for example B.sub.1). It was difficult to accurately separate these sheets into the desired batches. Also, because the sorting levers 7a-7d necessarily stopped the flow of the sheets, there was not a constant spacing of the sheets or articles in the pile, as is shown in FIG. 4(C). This caused disarray in the later processing of the article because the sheets would not be aligned.
Also, as FIG. 4(C) shows, the front edge of one article or sheet (for example B.sub.6) may lie against the back edge of the preceding sheet (B.sub.5) so that the flow of even later articles in the desired batch would be disturbed. Finally, as shown in FIG. 4(D), in order that the levers 7a-7d function as desired it is necessary that the edges thereof be higher than the surface of the sorting conveyor belts 6a-6e. It was, therefore, impossible, as shown in FIG. 3(A), for the sorting conveyor to have a full width conveyor belt. This made it impossible to apply a uniform braking power to the flat objects, further contributing to the disarray of the objects in the batch.
By the present invention these deficiencies of prior art conveyor devices have been eliminated and a conveyor device is provided which permits precise separation between the sheets or other articles in one batch and those in the following batch and which avoids misalignment and jamming of the articles. Any misalignment would have to be corrected in later processing, resulting in additional expense and perhaps requiring the temporary shutting down of the conveyor or the slowing of the conveyor. The conveyor structure of this invention is that of a twin-level or a multi-level conveyor in which the speeds of each component can be controlled. A conveyor structure is provided in which the position of the sorted or batched articles is accurate and it reduces disarray or misalignment in them to the absolute minimum.